JP2008-138685A (corresponding to U.S. Pat. No. 6,217,297B1) teaches an electric compressor, which is installable to a vehicle. This electric compressor is configured to be installed to a lateral surface of an internal combustion engine of the vehicle such that the electric compressor projects from the engine. The electric compressor is a rotating machine, which includes rotatable bodies, such as a rotor of an electric motor unit and a rotatable shaft of a compressor unit. As indicated in JP2008-138685A (corresponding to U.S. Pat. No. 6,217,297B1), the vibrations of the rotating machine are limited by improving a fixing structure of the rotating machine.
On the other hand, there is known a damper device, which is configured to oscillate to cancel vibrations (oscillations) of the rotating machine. For example, JPH03-271596A teaches a motion damper, which is installed in an inside of a rotary compressor. This motion damper includes an inertial body and a connecting body, and the connecting body connects between the inertial body and a case of the compressor.
Furthermore, JP2010-124591A teaches dampers installed in an inside of a dynamo-electric machine. Each damper includes a weight portion (serving as an inertial body) and a resilient member. The resilient member connects between the weight portion and a laminated iron core and is resiliently deformable in the radial direction. JP2010-124591A discloses the structure, which has the multiple dampers to damp the oscillations of multiple oscillation modes.
The damper device of JPH03-271596A cannot limit complicated oscillations generated in the rotating machine.
JP2010-124591A proposes to limit the complicated oscillations with the multiple dampers. However, in the prior art technique, the two dampers are installed in the rotating machine such that the two dampers are spaced from each other. In this structure, it is required to provide the installation locations, which are spaced from each other and to which the dampers are installed. Also, the number of steps, which are required to install the dampers, is disadvantageously increased.
Furthermore, in the prior art technique, the dampers are arranged to project radially outward of the rotating machine or to project axially outward of the rotating machine. With this kind of structure, the installation of the dampers in the inside of the rotating machine is difficult. Furthermore, the size of the rotating machine is disadvantageously increased.